在python中使用线程时如何创建文件？

Question

Have a look at this code :

import threading
import time

def my_inline_function(number):
    #do some stuff
    download_thread = threading.Thread(target=function_that_writes, args=number)
    download_thread.start()
    #continue doing stuff
    i = 0

    while(i < 10000):
        print str(i) + " : Main thread"
        time.sleep(1)
        i = i + 1


def function_that_writes(number):
    i = number

    file = open("dummy.txt", 'w')

    while (i < 10000):
        string = str(i) + " : child thread"
        file.write(string)
        time.sleep(1)
    file.close()

my_inline_function(5)
function_that_writes(5)

With does my_inline_function() , which starts a thread, not create a file?

But when I am calling a function_that_writes(...) directly, which is not running in a thread, it is able to create a file.

Why am I getting this behaviour?

Answer 1

You need to supply your argument as a tuple args=(number,) :

download_thread = threading.Thread(target=function_that_writes, args=(number,))

The exception is pretty clear here:

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/Users/mike/anaconda/lib/python2.7/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/Users/mike/anaconda/lib/python2.7/threading.py", line 754, in run
    self.__target(*self.__args, **self.__kwargs)
TypeError: function_that_writes() argument after * must be an iterable, not int